/* Lesson Plan stylesheet — print + screen */
:root {
  --bg: #fdfbf6;
  --surface: #ffffff;
  --text: #1c1917;
  --text-sub: #57534e;
  --text-muted: #78716c;
  --border: #e7e2d8;
  --border-strong: #d6cfbe;
  --accent: #d4541c;
  --accent-soft: #fef3ec;
  --green: #2d6a4f;
  --green-soft: #ecf6f0;
  --amber: #b45309;
  --amber-soft: #fef6e7;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(28, 25, 23, 0.05);
  --shadow-md: 0 4px 12px rgba(28, 25, 23, 0.08);
  --font-zh: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, "Helvetica Neue", Arial, sans-serif;
  --font-serif: Georgia, "Songti SC", "Source Han Serif SC", serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-en);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* Top bar */
.lesson-bar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 14px;
  box-shadow: var(--shadow-sm);
}
.lesson-bar a {
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
}
.lesson-bar a:hover { color: var(--accent); }
.lesson-bar .actions { display: flex; gap: 14px; align-items: center; }
.lesson-bar button {
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 8px 14px;
  min-height: 38px;
  font-family: inherit;
  font-size: 14px;
  cursor: pointer;
  color: var(--text);
}
.lesson-bar button:hover { background: var(--accent-soft); border-color: var(--accent); }

/* Body wrapper */
.lesson-wrap {
  max-width: 780px;
  margin: 0 auto;
  padding: 36px 28px 80px;
  background: var(--surface);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  min-height: 100vh;
}

/* Typography */
h1 {
  font-family: var(--font-serif);
  font-size: 30px;
  line-height: 1.25;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
  color: var(--text);
}
h2 {
  font-family: var(--font-serif);
  font-size: 22px;
  line-height: 1.3;
  margin: 36px 0 12px;
  padding-top: 18px;
  border-top: 2px solid var(--border);
  color: var(--text);
}
h2:first-of-type { border-top: none; padding-top: 0; }
h3 {
  font-size: 17px;
  line-height: 1.35;
  margin: 24px 0 8px;
  color: var(--accent);
  font-weight: 700;
}
h4 {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-sub);
  margin: 18px 0 6px;
}
p { margin: 0 0 12px; }
strong { color: var(--text); font-weight: 700; }
em { color: var(--text-sub); }
code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: var(--accent-soft);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--accent);
  overflow-wrap: anywhere;
  word-break: break-word;
}
hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 28px 0;
}

/* Lists */
ul, ol { margin: 0 0 14px; padding-left: 22px; }
li { margin: 4px 0; }
li > p { margin: 4px 0; }

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
  background: var(--surface);
  table-layout: auto;
}
th, td {
  text-align: left;
  padding: 8px 12px;
  border: 1px solid var(--border);
  vertical-align: top;
  overflow-wrap: anywhere;
}
th {
  background: var(--accent-soft);
  font-weight: 700;
  color: var(--text);
}
tbody tr:nth-child(even) { background: #fbf8f1; }

/* Blockquotes */
blockquote {
  margin: 16px 0;
  padding: 12px 18px;
  background: var(--amber-soft);
  border-left: 4px solid var(--amber);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-style: normal;
}
blockquote p:last-child { margin-bottom: 0; }
blockquote strong { color: var(--amber); }

/* Slide block — emphasized container */
h3 + p strong:first-child,
p > strong:first-child { color: var(--accent); }

/* YAML frontmatter (hidden, kept for source) */
.frontmatter { display: none; }

/* Print */
@media print {
  :root { --bg: #ffffff; }
  body {
    background: white;
    font-size: 11pt;
    line-height: 1.45;
  }
  .lesson-bar { display: none; }
  .lesson-wrap {
    max-width: none;
    margin: 0;
    padding: 0.5in;
    border: none;
    background: white;
    min-height: auto;
  }
  h1 { font-size: 22pt; margin-bottom: 6pt; }
  h2 {
    font-size: 14pt;
    margin: 18pt 0 6pt;
    padding-top: 10pt;
    page-break-after: avoid;
  }
  h3 {
    font-size: 12pt;
    page-break-after: avoid;
    color: #b8451a;
  }
  h4 { font-size: 9pt; }
  code { background: #f4f1ea; color: #1c1917; }
  table { font-size: 9pt; page-break-inside: avoid; }
  th { background: #f4f1ea; }
  tbody tr:nth-child(even) { background: white; }
  blockquote {
    background: #f9f4ea;
    page-break-inside: avoid;
    border-left-width: 2pt;
  }
  /* Quick Reference Card (section 12) gets its own page — stable id-based selector. */
  #section-12 { page-break-before: always; }
  ul, ol { page-break-inside: avoid; }
  a { color: black; text-decoration: none; }
  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 8pt;
    color: #888;
  }
}

/* Lesson index page */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.lesson-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: transform 120ms ease, box-shadow 120ms ease, border-color 120ms ease;
}
.lesson-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.lesson-card .lc-num {
  font-family: var(--font-serif);
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}
.lesson-card .lc-title {
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.3;
  margin: 0;
}
.lesson-card .lc-meta {
  font-size: 13px;
  color: var(--text-sub);
}
.lesson-card .lc-actions {
  margin-top: auto;
  padding-top: 8px;
  display: flex;
  gap: 8px;
}
.lesson-card .lc-actions a {
  flex: 1;
  text-align: center;
  padding: 6px 10px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  color: var(--text);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
}
.lesson-card .lc-actions a.primary {
  background: var(--text);
  color: white;
  border-color: var(--text);
}
.lesson-card .lc-actions a.primary:hover { background: var(--accent); border-color: var(--accent); }
.lesson-card .lc-actions a:hover { background: var(--accent-soft); }

/* Featured card — Workshop 01, "start here" */
.lesson-card--featured {
  grid-column: 1 / -1;
  padding: 26px 28px 24px;
  background: linear-gradient(135deg, var(--accent-soft) 0%, var(--surface) 65%);
  border-left: 4px solid var(--accent);
  position: relative;
}
.lesson-card--featured .lc-badge {
  display: inline-block;
  align-self: flex-start;
  background: var(--accent);
  color: white;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  margin-bottom: 4px;
}
.lesson-card--featured .lc-title {
  font-size: 24px;
  line-height: 1.25;
}
.lesson-card--featured .lc-tagline {
  margin: 4px 0 6px;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--text-sub);
  max-width: 62ch;
}
.lesson-card--featured .lc-actions { padding-top: 12px; max-width: 360px; }
.lesson-card--featured:hover { border-color: var(--accent); border-left-color: var(--accent); }
@media (max-width: 560px) {
  .lesson-card--featured { padding: 20px 18px; }
  .lesson-card--featured .lc-title { font-size: 20px; }
}

/* Language toggle visibility (matches hub pattern) */
.zh, .en { display: inline; }
body.zh .en { display: none; }
body:not(.zh) .zh { display: none; }
body.zh { font-family: var(--font-zh); }

/* Lesson page intro banner */
.intro-banner {
  background: var(--green-soft);
  border-left: 4px solid var(--green);
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  margin: 18px 0 24px;
  font-size: 14px;
  color: var(--text);
}
.intro-banner strong { color: var(--green); }

/* ---- summary video embed ---- */
.lesson-video { background: var(--surface); border: 1px solid var(--border); border-left: 4px solid var(--accent); border-radius: var(--radius-lg); padding: 20px 22px; margin: 0 0 28px; box-shadow: var(--shadow-sm); }
.lesson-video .lv-head h2 { margin: 0 0 4px; font-size: 20px; }
.lesson-video .lv-head p { margin: 0 0 16px; font-size: 15px; color: var(--text-sub); }
.lv-body { display: flex; gap: 22px; align-items: flex-start; }
.lv-body video { flex: 1 1 auto; width: 100%; max-width: 560px; aspect-ratio: 16 / 9; background: #1c1917; border-radius: var(--radius-md); border: 1px solid var(--border); }
.lv-side { display: flex; flex-direction: column; align-items: center; gap: 8px; flex-shrink: 0; }
.lesson-video-qr { width: 108px; height: 108px; background: #fff; padding: 6px; border: 1px solid var(--border); border-radius: var(--radius-sm); }
.lesson-video-qr canvas, .lesson-video-qr img { display: block; width: 100% !important; height: 100% !important; }
.lv-qr-cap { font-size: 13px; font-weight: 600; color: var(--text-sub); text-align: center; }
.lv-alllink { font-size: 14px; font-weight: 600; color: var(--green); text-decoration: none; }
.lv-alllink:hover { text-decoration: underline; }
@media (max-width: 600px) { .lv-body { flex-direction: column; } .lv-side { flex-direction: row; align-self: flex-start; } }
@media print { .lesson-video { break-inside: avoid; border-left-color: #999; } .lesson-video video, .lv-alllink { display: none; } .lv-body { gap: 14px; } }